The cryptocurrency sale of the pear-shaped D Flawless diamond, named "The Key 10138," shows Sotheby's "commitment to innovation," the company said.
"Diamonds are keys to understanding the history of the Earth, reminding us of our human condition and the transcendental power of beauty," Wenhao Yu, Deputy Chairman of Sotheby’s Jewellery in Asia, said about the sale.
"With the name ‘The Key 10138,' we wanted to celebrate this enlightening virtue, while also alluding to the crucial function of digital keys in the world of NFTs and cryptocurrency."
The auction house accepted Bitcoin or Ether through Coinbase, a cryptocurrency exchange that went public earlier this year.
It's far from Sotheby's first foray into cryptocurrency.
In May, during an auction headlined "DISRUPTOR OF ART MEETS DISRUPTOR OF FINANCE," Sotheby's sold a piece of artwork by Banksy for $12.9 million in cryptocurrency.
A month before that, Sotheby's accepted cryptocurrency for a batch of non-fungible tokens, or NFTs, which are unique digital assets that use blockchain technology to verify scarcity.